The subject matter herein relates generally to terminal crimping devices using ultrasonic transducers.
Terminals are typically crimped onto wires by means of a conventional crimping press having an anvil for supporting the electrical terminal and a ram that is movable toward and away from the anvil for crimping the terminal. In operation, a terminal is placed on the anvil, an end of a wire is inserted into the ferrule or barrel of the terminal, and the ram is caused to move toward the anvil to the limit of the stroke of the press, thereby crimping the terminal onto the wire. The ram is then retracted to its starting point.
New technologies in ultrasonic monitoring have been proposed for use in crimp quality monitoring. For example, U.S. Pat. Nos. 7,181,942 and 8,490,463 describe ultrasonic devices and methods for measuring crimp connections by comparing signals with signals from a previous crimp that was determined to be desirable through destructive testing.
Such ultrasonic monitoring systems are not without disadvantages. For instance, the ultrasonic monitoring systems typically measure the quality of the crimp by transmitting the ultrasonic signals when the ram is at a bottom limit of the stroke of the press. While the ultrasonic signals sampled at the bottom limit of the stroke provide one indicator of the quality of the crimp, the measurement does not reveal defects inside of the crimp that may have been created before the crimp is fully developed. The defects may be caused by factors such as using the wrong terminal or wire size, missing strands of wire, using the wrong wire type, incorrect stripping of insulation, and/or the like. Since such defective crimped connections frequently have the appearance of high quality crimp connections, it is difficult to identify these defects so that timely corrective action may be taken.
A need remains for a crimp quality monitoring system that uses ultrasonic monitoring to determine crimp quality.